


Do A Science

by Misfit_McCoward



Category: Naruto
Genre: Demonic Possession, F/F, Gen, Karin is a shameless flirt and she will NOT be toning it down and she will NOT be apologizing, Science, Science Experiments, Science Girlfriends, but NO tags for ladies getting their science on, pipet tip based subplots, why do we have science boyfriends and science husbands and science bros as tags
Language: English
Status: In-Progress
Published: 2020-12-28
Updated: 2021-01-02
Packaged: 2021-03-11 00:09:03
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 17,670
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/28375971
Author URL: https://archiveofourown.org/users/Misfit_McCoward/pseuds/Misfit_McCoward
Summary: “Youdohave a plan,” Sakura prompted, doubt flickering in her eyes, “don’t you, Sasuke-kun?”“We use…” Sasuke started, and then suddenly became acutely aware of a bead of sweat rolling down his back, “...science?”--Sasuke learned a great many skills from Orochimaru. The scientific method was not one of them.OR: A fic where Team Seven and Team Taka unite to ruin Sasuke’s life.
Relationships: Dai-nana-han | Team 7 (Naruto) & Team Hebi | Team Taka, Haruno Sakura/Karin
Comments: 37
Kudos: 158





	1. Day 1

**Author's Note:**

> Pandemic brain went, "I bet Sasuke doesn't know S H I T about science," and instead of just ignoring this thought like a normal person, I wrote a whole fic about it. 
> 
> Okay, so, it is important for this fic that the reader understands how pipets work. Specifically, [this type of micropipette.](https://bio305lab.wdfiles.com/local--files/appendix:pipettes/pipetteImages_1.jpg) It's explained/described in text but it's probably easier to get with the linked diagram!

On the bright side, the Kyuubi likely saved Naruto from having his soul ripped to shreds by the temple seal. Unfortunately, the seal and the Kyuubi’s demonic chakra had interacted… oddly. 

**“AND THE SEAS WILL RISE, AND THE INNOCENT WILL DROWN IN BLOOD,”** Naruto screamed. Black sludge poured from his mouth, and purple slime oozed from his skin. Kakashi’s seals had at least gotten the horrifying black chakra at bay.

“Did you know,” Sakura quipped to Sasuke as she worked to fix up his arm, which Naruto had snared with one of his extra six demonic arms, “that this bullshit never happens when I go on missions with _ literally anyone else?” _

Kakashi edged around Naruto’s twitching form. He’d wrapped Naruto in ninja wire, then slapped as many demon containment seals as possible on him. Three of the demonic arms had shriveled away to nothing, and the purple ooze no longer smelled like the shinigami’s stomach. 

**“THE DARK GOD WILL PEEL YOUR SKIN AND FLAY YOUR CHILDREN,”** Naruto threatened. 

“That’s nice,” Kakashi answered. “Sasuke, I think I got him. You can let him go.”

Sasuke relaxed his sharingan from mangekyou back to its base form. Naruto twitched as the sharingan’s control fell away, but didn’t fight his restraints beyond yelling more threats at them, gurgling the black sludge as he screamed. Sakura clicked her tongue and moved on to checking Kakashi over. 

“How long is that going to hold?” Sakura asked, hands glowing green. “It’s going to take a few days for anyone from Konoha to get here…”

The three of them fell into silence as they thought the problem over, Naruto continuing to scream about the dark god and streets running with blood. It was only slightly more deranged than Juugo on a bad day, and now that he was contained, easy enough to ignore long enough to think. 

Sasuke wiped sweat from his brow and examined Sakura’s work on his lone arm. She hadn’t had enough time to heal it completely, and his sleeve was shredded and covered in blood, but the three long scratches had been reduced to a soft pink. He felt no more pain. 

This was supposed to be an easy B-rank to grab some treasures from a temple. Sasuke had nearly forgotten how horribly wrong all of Team Seven’s missions went. It was almost nostalgic. 

**“...AND YOUR INTESTINES SHALL BECOME FODDER FOR THE DARK GOD’S SPAWN,”** Naruto bellowed. 

Sasuke ripped off his empty sleeve, crossed to Naruto’s prone form, and jammed the fabric into his mouth. 

In the best case scenario, Team Seven would keep Naruto under control for three or four days and a team of sealing specialists from Konoha would show up and undo the temple seal. In the worst case scenario, it would take over a week for anyone to find them out here in the middle of nowhere, and then the sealing specialists wouldn’t know what to do either. 

Team Seven did not specialize in containment. Sure, Kakashi knew a handful of seals that would last for a while, and Sasuke could hold demons at bay for as long as he had chakra to fuel his mangekyou, and Sakura knocking a mountain on top of Naruto had been effective for a few hours, but…  _ but. _ Not even they had the stamina to keep this up for a week. They needed to act now.

“I’ve got an idea,” Sasuke announced, turning to his non-possessed teammates. 

They both raised their eyebrows at him, like he’d said something cute. Sasuke felt a flicker of longing for Team Taka, who never questioned any of his leadership decisions. 

“There’s an old Sound hideout near here,” Sasuke continued. “There might be something there that can help.”

Kakashi and Sakura exchanged a look-- a look that Sasuke found annoyed him because he didn’t understand it-- and Kakashi told him to lead the way. 

It was a little tricky to move Naruto, and Sakura ended up breaking his spine after promising she could put him back together. Naruto healed it himself by the time they located the entrance to the abandoned hideout and went right back to trying to kick them with his new cloven hooves. 

Sasuke had never been to this exact hideout, but they all had similar layouts to facilitate shinobi rotating through them. It wasn’t difficult to locate and disarm all the traps at the entrance, and it only took a few minutes to find Orochimaru’s lab. 

Every hideout had a lab. It was Orochimaru's favorite pastime. 

Sakura surveyed the lab with bright-eyed curiosity as Sasuke flicked on the lights, the generator miraculously still in order. Kakashi looked around with a much warier expression, even as he knelt to re-tie Naruto’s horrible little demon hooves. 

“Okay,” Sakura said when the lab was fully illuminated. “Now what?”

She smiled at Sasuke expectantly. 

Sasuke stared back at her. 

“You  _ do _ have a plan,” she prompted, doubt flickering in her eyes, “don’t you, Sasuke-kun?”

“We use…” Sasuke started, and then suddenly became acutely aware of a bead of sweat rolling down his back, “...science?”

Sakura’s smile took on a decidedly fixed quality. 

Orochimaru had taught Sasuke a great many things. He’d passed on his snake-summoning contract and showed Sasuke the ins and outs of several forbidden jutsu. He had not, however, ever even offered to let Sasuke so much as hold a pipet. 

Sasuke’s plan was to do a science. He just didn’t know how, or what that meant, exactly. 

“You’re a medic,” Sasuke told Sakura, waving at the lab bench behind him. “You know how to use this stuff, right?”

Sakura’s eyes moved from Sasuke’s hand to the exact instrument he happened to be pointing at. 

“I know how to use a pH meter, yes,” she said flatly. “I’m not sure how  _ my _ lab expertise is going to help us, unless you have a biopsy and you want to know if it’s cancer or not.” 

Months ago, back when they were still fighting a deranged moon goddess, Sasuke had decided he really liked this new version of Sakura who didn’t take shit from anyone. Now that she was eyeing him like a hospital trainee who couldn’t even find a pulse, he was less sure. 

Kakashi cleared his throat. 

“Sakura, you have training in chakra corruption, yes?” he asked. 

Bizarre medical conditions were, at least, a topic Sasuke had bothered to listen to Orochimaru grouse about. Chakra corruption was a pretty rare condition, but it could happen to shinobi. There was a clan in Kiri that specialized in it, once, but they’d been wiped out in Yagura’s genocide. Sasuke doubted Sakura had ever seen it in person, unless Konoha shinobi got into some  _ really _ weird stuff while Sasuke was away. 

“I’d feel better consulting with a sealing specialist,” Sakura muttered, but turned to the bench and started opening drawers and cabinets anyway. 

The lab had two blacktopped workbenches, each with a sink at the end, plus a series of low tables along one wall with microscopes and odd machines of various shapes and sizes. Another wall was all shelves of books and scrolls, and the back wall had two cabinets of glassware and a line of refrigerators and freezers. The hum of the freezers was distinctly lacking-- not all of them had survived the years of lack of maintenance. 

The final wall had chemical storage and a fume hood. They dropped all their stuff at the bottom of the hood, including Naruto. 

Naruto immediately kicked open the door of the cabinet under the hood. The door read FLAMMABLE CONTENTS. Kakashi cocked his head and dragged Naruto to a corner with less dangerous looking things.

Most of the drawers under the workbenches had hand-written labels that said things like  _ tubes _ and  _ racks _ and  _ extra flint. _ Sasuke recognized the handwriting as Kabuto’s; Orochimaru was the type of person who revelled in “organized mess” and would never label anything. Based on the wrinkle at the bridge of Sakura’s nose as she rifled through them, Orochimaru hadn’t maintained Kabuto’s careful system. 

Sakura moved on to rummage through what was on top of the lab benches, as well as what was in the shelves above them. The benchtops had all sorts of random pieces of smaller equipment, mostly boxy beige machines with no obvious purpose to Sasuke. The shelves were almost entirely pyrex bottles of clear liquids with handwritten labels, the occasional roll of tape, and a pile of boxes of gloves. 

“What size are you two?” Sakura asked, pulling on a pair of dark blue gloves. 

Sasuke hadn’t even known gloves  _ came _ in sizes. 

_ Powder-free sterile nitrile gloves, _ the boxes advertised. They weren’t latex? Why would they be powdered?

“Extra large,” Kakashi drawled. The presence of tens of glass bottles of potentially dangerous liquids was probably the only thing that kept Sakura from hitting him. “Do you need an extra set of hands, then?”

Naruto took that moment to let out one very long scream, then flopped over and knocked over a rack of lab coats no one in Sound ever used. Except Karin, occasionally, to keep bleach off her clothes.

(“Do you like it?” Karin had asked. She’d buttoned exactly one button, at her natural waist to accentuate her figure under the otherwise boxy coat. She gazed coyly at him over the rims of her glasses.

“Shouldn’t you close it all the way, if you’re trying to protect your clothes?” Sasuke asked. For some reason, this made Karin scowl. 

Sasuke didn’t really see why. He went around with his shirt completely undone; it wasn’t like he was judging her. It was just that she’d  _ literally _ just said she was putting on the coat so she didn’t ruin her clothes. 

“God, sometimes you’re a fucking moron,” Suigetsu said from the column of water they kept him in when he wasn’t running missions or washing out test tubes. 

“I’ll turn your temperature controls up to boiling!” Karin shrieked back at him.

“You’re only wearing that stupid coat so you can pretend you’re a real scientist and not a test subject with privileges-- hey, no, what are you-- NO, SASUKE, HELP!”)

Sasuke’s old team… would actually be way more helpful than Sasuke in this situation. 

“I’m going to send a summon to see if anyone from Team Taka is nearby,” Sasuke said, and a tiny snake plopped from his sleeve. “They might be able to help.”

Sakura’s mouth twitched in a half-smile as the snake slithered off. 

“That’s good,” she said. “In the meantime…”

She held out a box of size medium gloves to him. Kakashi was currently wrestling some more ninja wire onto a screaming Naruto, and had said something about making more restraint seals. 

Sasuke stared at the box. Should he feel judged that Sakura had sized him as a medium?

“It’s best to go a size down with gloves,” Sakura said, as if reading his mind. There was a teasing, mean glint in her eye. “It improves dexterity.” 

Sasuke took one. 

“I’ll help you tape up your sleeve while we’re at it,” Sakura continued, pulling a roll of tape down from a shelf. “You don’t want to knock something over or set it on fire.”

Ah yes, bunsen burners. Sasuke knew these were frequently used in lab. He did not know why. 

Sasuke was adjusting well to having one arm, but he still needed Sakura’s help to tape the cuff of his sleeve closed and then put the glove on. He probably could have figured it out himself, with a few minutes of experimentation, but he found he didn’t mind Sakura’s assistance. He remembered being thirteen and bed-ridden and furious with her just for peeling an apple for him, like she’d been telling him he was too weak to take care of himself. He still hated having to seek help, but Sakura approached it with a sort of clinical assessment and none of her past wobbly-faced and humiliating sympathy. 

Sasuke was also, arguably, more mature now than he had been at thirteen. He understood it was normal and alright to depend on others, even if he hated it. 

Sakura was slipping into full-on medic mode now, lecturing Sasuke while pulling out instruments and tubes from cabinets and pulling down bottles of unknown liquids from the shelves. 

“The first step is diagnostics-- we need to figure out what’s actually happening to Naruto’s chakra,” Sakura said, handing Sasuke something that he recognized as  _ probably _ a pipet. “If it’s exogenous chakra, or only some of Naruto is corrupted, we should be able to just syphon off the corrupted chakra.”

“Or seal it,” Sasuke added. Exogenous chakra. Chakra from outside the body. Yes. He knew about that one; it was how his cursed seal had worked. 

Sakura set a bottle of clear liquid down in front of Sasuke. “Or seal it,” she agreed. “That’s probably what we’ll have to do if it’s the Kyuubi’s chakra that’s corrupted. If  _ all _ of Naruto’s chakra or  _ all _ of the Kyuubi’s chakra is affected though…”

At twelve years old, the thought of a potential unfixable problem probably would have made Sakura’s lip tremble in fear and make her demand assurances from the rest of Team Seven that everything was going to be alright. At eighteen, Sakura had been through war. Her eyes just went hard and grim. 

“We’ll figure something out,” she finished. “He’s Naruto; he can make it through anything.”

This was true. This was the only reason Team Seven wasn’t completely freaking out. 

“We can do some basic stoichiometry to see how much of Naruto’s chakra is in there,” Sakura continued, and then Sasuke completely lost the plot. “The Ito-Senju method is old fashioned, but we have the reagents for it.”

The Ito-Senju… what? Sasuke wasn’t even sure if the thing in his hand was a pipet. 

“...so you just make a serial dilution of Reagent B, and I’ll naturalize Reagent A to Naruto’s corrupted chakra,” Sakura kept going, glaring at a bottle of honey-colored liquid. There was a layer of red-brown flakes sitting at the bottom. “Although it looks like Reagent A came out of solution. I think I’ll have to make a new one…”

“Sakura,” Sasuke said. She blinked at him, her very serious and in-charge medic face falling away ever so slightly. “I have no idea what you’re talking about.”

“It’s a test for chakra contamination,” Sakura said, as if she were reminding him of something basic that they learned at the Academy. Sasuke wasn’t at the very top for written scores, but he was close enough that he could confidently say they didn’t learn diddly-squat about chakra contamination at the Academy. 

“In this case,” Sakura continued, “if we treat Naruto’s non-corrupted chakra as the contaminant, we can stoichiometrically determine if it’s still present, and how much is there.”

Sasuke still didn’t know what stoichiometry was, and at this point, he was too afraid to ask. 

Sakura had to walk him through what a serial dilution was. Basically, he was going to take whatever this Reagent B was, and make increasingly higher dilutions of it in water. This, he felt confident he could do. Taking care of himself and his home as an orphan, he’d had to do similar things when cooking, or when preparing cleaning solutions. It was fine. 

“Oh, but boil the water first, will you?” Sakura continued, now pulling random binders from a shelf of books and scrolls across the lab. “It looks like there’s a filter on the sink, but who knows when it was replaced…  _ Why _ doesn’t this place have a proper protocol book?”

Kakashi, having rebound and re-gagged Naruto, moved to help Sakura find… the recipe for whatever Reagent A was, or something. He also said something about checking the scrolls for better seals for containment and restraint. 

Sasuke turned to the task at hand. Sasuke was a decent cook, and boiling water was something he could totally do. He put down the maybe-pipet and moved to the sink. There was a peg board above the sink, from which an array of glassware hung. Sasuke remembered watching Suigetsu wash this type of stuff out, in another lab; he knew the stuff above the sink was clean. 

He filled a beaker with water. Step one: complete. 

The bunsen burner only took a few minutes of fumbling around to figure out. It was connected by a tube to a tap labeled GAS and worked the same as any gas stove. Turn on gas, light it on fire. Easy. Sakura had even left Sasuke a flint striker, which he ignored because he’d been using fire jutsu to light camping stoves for his entire shinobi life. 

Sasuke stared at the blue flame for a few seconds, listening to Sakura try to explain to Kakashi what he was helping her look for. This was interjected with complaints about how normal labs just kept all their recipes and protocols in one book. 

(“I… I forgot what he said to do,” thirteen-year-old Karin said, cheeks red. Kabuto just raised his eyebrows. 

“You could have just taken notes,” he pointed out. “That’s what the notebook is for.”

“No one  _ else _ takes notes,” Karin replied. She kept her eyes averted. Sasuke couldn’t tell if it was meant to be out of respect to Kabuto’s seniority or embarrassment that she couldn’t remember what Orochimaru had explained. “I thought I’d remember.”

Sasuke was beginning to suspect he wasn’t here to see Karin’s “cool new experiment,” and rather because she knew Kabuto wouldn’t do anything to her if Sasuke was standing right there. It seemed like a  _ lot _ of the lab staff ended up mysteriously missing, or involved in freaky experiments. Everyone was expected to make Orochimaru’s new star apprentice happy, though. Even Kabuto. Even if it meant being nice to a brand new lab worker who hadn’t thought to write instructions down. 

Years later, Karin would rage at Sasuke about how no one in the lab ever bothered to record what they did properly, ever, and how she was wasting hours going through and annotating more senior researcher’s notebooks, because otherwise everyone was just being wildly inefficient with how information was passed on. 

“Karin really shines at management,” Orochimaru had said, when Sasuke had brought it up to him on Karin’s behalf. 

Organizing the lab meant organizing Orochimaru himself, which was a futile task. Two months later, Karin’s efforts were rewarded by being shipped off to organize and manage a prison instead.)

Sasuke wondered if Karin had even known Orochimaru ran an atypical lab with a horrible culture of disorder and lazy record keeping, compared to whatever a normal lab was. Sasuke himself hadn’t even realized that other labs might be set up differently. Apparently the Konoha hospital lab had systems in place so tasks could be passed between lab workers without everyone getting confused. Orochimaru enjoyed pitting his workers against each other too much to enforce anything like that. 

Sasuke blocked out Sakura’s whining and looked around for something to hold the beaker of water over the bunsen burner’s flame. He knew he’d seen people construct elaborate metal contraptions to hold test tubes and flasks over flames. 

Nothing jumped out at him as useful. Sasuke just held the beaker over the open flame with his bare hand. He was an Uchiha. He was made for handling hot objects.  _ This was fine. _

He boiled the water for ten minutes, because that was how long you were supposed to boil it for drinking water in the field. It wouldn’t get rid of any minerals in the water, but it should kill any micro-organisms that might contaminate it with their own chakra. 

At least, that was what Sasuke assumed he was doing. He still wasn’t quite clear on what the test Sakura wanted to do was. 

He picked the pipet back up and examined it. Rather than glass with a rubber bulb, like they tended to have in movies, it was all hard, beige plastic with dark blue disc at the top he could press down with his thumb. There was a dial on the side with some numbers, currently displaying  _ 1000. _ Sasuke did not know what the numbers meant. Some type of… unit?

He stuck the bottom of the pipet into his beaker of hot water and pressed the… disc? plunger? down. 

Nothing happened, except that he got the pipet wet. 

“Sasuke-kun,  _ no!” _ Sakura suddenly yelled, and sprinted over to him. “You need a tip!”

“...what?” Sasuke asked as Sakura snatched the pipet right out of his hand. 

“Ah, I hope the filter inside worked,” Sakura continued, examining the pipet, voice laced with worry. 

“Sakura,” Sasuke pressed. 

“Yes, Sasuke-kun, sorry,” Sakura said, turning to him. In a very stressed voice, she said, “I shouldn’t have assumed you knew how to use one of these. You need to use one of the pipet tips.”

Sakura pulled forward a plastic box she’d set out for him and opened it to reveal a hundred or so pieces of clear plastic, arranged in neat rows. The plastic was conical in shape, with the hollow bottoms facing upwards. Sakura demonstrated how the bottom of the pipet fit perfectly into the opening of the pipet tip, and that the clear plastic part could be filled with precise amounts of liquid, determined by the dial on the side of the pipet. Then the whole tip could be ejected, so that a new, sterile tip could be switched out without having to clean the pipet itself between uses.

As she talked, she sounded more and more like she was lecturing a dumb genin and not her teammate she’d fought a literal goddess with. 

“Getting liquid in the pipet could really damage the internal mechanism,” Sakura said, sounding alarmingly like Iruka-sensei when he told Sasuke off for coming into class covered in burns from fire jutsu practice. “You’re lucky it looks like the filter caught it all, but--”

Sasuke had managed to keep his thoughts to himself for her explanation, but now she was giving him flashbacks to the Academy.

“You could have just explained all that before,” he answered tightly, “instead of just leaving me to figure it out on my own.”

Old Sakura would have backed off and apologized immediately. New Sakura’s eyebrow twitched. 

“And  _ you _ could have said you didn’t know how to use a pipet,” she countered. “I’m sort of worried about a lot here, Sasuke-kun, I don’t have time to think about--”

“Maa, maa, we’re all worried,” Kakashi said, coming up behind them. In the background, Naruto made muffled screams through his gag. 

Sakura took a deep breath. 

“Sorry,” she repeated. “I’m just-- it’s my responsibility to take care of Naruto’s health, but I don’t know nearly enough about non-medical seals to do very much--”

“It’s okay,” Kakashi said, putting both hands on her shoulders. “There’s plenty of information on fuuinjutsu sitting around here, and I sent an update to Konoha about our exact location. We’ll figure something out.”

Sasuke watched this exchange in awkward silence. It made him feel… well, he’d been disconnected from Team Seven for  _ years, _ even if they’d started running missions together, and this was a harsh reminder of all the connections they had made that he’d missed out on. He wouldn’t have been able to calm Sakura down like this if he tried, and he hadn’t even realized Kakashi could  _ do _ comforting. 

In a couple months, Kakashi would be officially sworn in as Hokage, Sakura would start her transition into head of Konoha Hospital, and Naruto would start a long-term research mission to study the fuuinjustu materials he’s inherited from Jiraiya and his parents. Team Seven would be disbanded again, and Sasuke would never get another chance to figure out how he fit into this new dynamic. 

He did, actually, have some responsibility to Sakura to make sure she understood the breadth and limits of his capabilities instead of letting her grab blindly around in the dark for something useful. Sasuke was the one who’d offered up the lab; it wasn’t a huge leap on Sakura’s behalf to assume he at least knew how to use a _ pipet. _ Even Suigetsu, who only ever did grunt work in the lab, probably knew how to use one. 

Sasuke had formed and captained his own team. He could totally reach out to her, instead of the other way around. 

“You want to monitor Naruto’s chakra, right?” Sasuke said, activating his sharingan. “What exactly so you want to know? I don’t understand what this test is for.”

Sakura just stared at him, mouth slightly open. She stared him right in the eyes, which was sort of novel and… nice. 

It was  _ nice, _ okay, for people outside of Team Taka to look him in the eyes. 

“I’m a moron,” Sakura breathed. “I totally forgot--”

“It’s okay,” Sasuke and Kakashi interrupted her in unison. 

It was sort of Sasuke's fault too, for not reminding her about the chakra-seeing eyes. It wasn’t like Sakura was used to working with someone with a sharingan on  _ medical _ issues. He just grunted at her while she whirled him around and pushed him at Naruto. He hoped she understood. 

(“She’s just mad because she forgot I can’t drown and got  _ upset,” _ Suigetsu griped. “Karin is such a bitch.”

Sasuke thought this was a bit unfair. Karin was a bitch by her own admission, yes, but she was a bitch who’d gotten genuinely upset when she thought Suigetsu had potentially died.

“Did you tell her what you were doing when you let yourself get sucked into a whirlpool?” Juugo asked calmly. 

“Why would I?” Suigetsu said, crossing his arms. “She literally kept me in an  _ aquarium tank _ for years--”

“Karin didn’t have control over what Orochimaru did,” Sasuke reminded him. He’d assembled this team less than a month ago and he’d… severely underestimated the interpersonal issues between Karin and Suigetsu. 

He’d assumed the biggest problem would be preventing Juugo from losing his mind and killing everyone around him. He was very wrong. 

“You should apologize,” Juugo said. 

“Why?” Suigetsu asked. _ “She’s _ the one who beat me with a chair and then locked herself in the hotel room-- which I’d like to sleep in tonight, by the way--”

Sasuke ended up renting a second hotel room, which Karin got to herself because Sasuke had to share with Juugo due to the “lose his mind” situation. Offering the room to Suigetsu-- because he  _ was _ the one Karin had tried to beat to death-- had prompted some very weird accusations from Suigetsu about Karin “sneaking into Sasuke’s bed.” Sasuke didn’t get what that was about, because he’d definitely been stuck in a snowstorm with Suigetsu before and snuggled with him. Sasuke was very warm, after all. 

Maybe Suigetsu was jealous…? 

The point was, Karin got her own room to split them up, and they both  _ still _ ended up mad about the situation. Sasuke still had no idea what the correct call there would have been, because both of them had just been… dumb teenagers.)

_ God, no wonder Kakashi always seemed out of his depth, _ Sasuke thought. 

Kakashi had painted a new seal around Naruto in old ink he found in the lab. It didn’t seem to be hugely effective, and Naruto was still occasionally thrashing around. Kakashi kneeled in the middle of the seal to pin him down while Sasuke studied him. He ignored the weird purple slime gushing over his fingers-- at this point, all of them were covered in it. 

“Okay,” Sakura said, right in Sasuke’s ear. It had taken a lot of work for Sasuke not to feel paranoid and tense about Sakura constantly standing right behind him. 

Apparently, it was the typical medic-nin position. Mostly, it just sent Sasuke’s shinobi brain into a panic of calculations between if Sakura was more likely to save his life or snap his neck. When he’d mentioned it to Naruto, Naruto had just looked at him like he was insane, because  _ Sakura was team medic. _ Of course she was there to help. 

Still. It felt  _ weird. _

Sakura asked Sasuke several rapid-fire questions about what Naruto’s chakra looked like, and if Sasuke could see any details of what the seal was doing. She also asked if the Kyuubi’s chakra was affected, and to what extent.

Naruto’s jinchuriki seal was good enough that Sasuke couldn’t quite pick up the Kyuubi’s chakra with a normal sharingan, so he let his eyes switch into mangekyou. Using it still hurt and took up tons of chakra, but Sakura had confirmed that his transplanted eyes weren’t ripping his retina to shreds. 

(It had, actually,  _ really _ bothered her, because it made no medical sense. Sasuke didn’t see what the fuss was. If it worked, it worked.)

Sasuke squinted, slowly pacing around Naruto one-hundred-eighty degrees. 

“Most of Naruto’s chakra is corrupted,” Sasuke concluded. “But it looks like his jinchuriki seal is protecting some of it.”

Naruto made chakra faster than anyone Sasuke had ever met. As new chakra bubbled up from his heart-- the seat of chakra production-- a small portion of it went into the jinchuriki seal and stayed normal, but most of it was slowly taken up by the temple seal, jumbled up, and spat back out again as corrupted chakra. If Naruto naturally produced chakra more slowly, or if he didn’t have the jinchuriki seal, the temple seal would have eaten all the way through his chakra reserves by now. 

Worryingly, because the jinchuriki seal let out miniscule amounts of the Kyuubi’s chakra into Naruto’s system, some of that was also being sucked by the temple seal. 

While Sasuke talked, Sakura’s face went very grim, and she kneeled by Naruto and released some mint green medical chakra into him. That, too, got sucked up into the temple seal and corrupted. 

“So it’s bad,” Kakashi concluded, stepping away from Naruto’s body as Sakura finished her experiment, “but not unsalvageable.”

Kakashi was confident he could modify Naruto’s jinchuriki seal to pull in more of Naruto’s chakra without destabilizing it. He wandered off into the lab to gather supplies, and Sakura sat back on her heels and bit her thumbnail.

“What are you thinking?” Sasuke asked. 

Sakura’s eyes flicked up to him. “That was really useful, thank you,” Sakura started. Sasuke really didn’t get how she was still constantly thanking and apologizing to people-- it would never even occur to anyone in Sound to talk to anyone but Orochimaru himself like that. 

And even then, no one would be genuine about this many  _ thank yous _ and  _ I’m sorrys.  _

“I think I can…” Sakura started and trailed off. She stood, slowly, still frowning down at Naruto. “I have no idea how to remove the seal, which is probably the only way to make Naruto better again. But I might be able to pull off all the corrupted chakra, and that will at least make him… normal again, for a while, and we can get back to Konoha.”

“That sounds promising,” Sasuke said lamely. Should he tell her she was doing a good job? Was that how Konoha-nin talked to each other? “What can I do to help?”

Sakura’s face immediately took on a very strained quality, and Sasuke interpreted this as Sakura giving herself a stomach ache trying to figure out a polite way to tell Sasuke he was, in fact, basically useless in this situation. 

“I can go figure out dinner,” Sasuke suggested before Sakura made herself sick. 

He left the Sakura and Kakashi to work in the lab, wandering further into the base. 

Not all of the base had working generators, but the main kitchen and adjacent storage room thankfully did. The kitchen was a huge, industrial-style place, with multiple counters and stove tops and ovens, for feeding tens and possibly hundreds of shinobi. 

Sasuke didn’t bother with the walk-in or any of the freezers, as he was sure that since the hideout had been abandoned for at least a couple years, whatever was inside had thawed out at least once. Instead, he pulled a bunch of canned and pickled vegetables from room temperature storage, along with some bouillon cubes and a sealed bag of dry rice. 

He cooked everything, including the rice, in chicken stock, because he didn’t really trust canned vegetables to be flavorful. The outcome was better than anything most shinobi would bother with on a field mission, but Sasuke was still frustrated he wasn’t doing more to help Naruto, and he went out of his way to prepare two types of sauce, along with a minimalist version of a Water Country dessert from canned coconut milk and agar powder. 

Sasuke didn’t even like sweets. Sakura and Kakashi better appreciate him. 

When he went back into the lab to announce dinner was ready, Sakura was glaring down a microscope’s eyepiece and lecturing Kakashi as he stood over her. When Sasuke approached, Kakashi caught his eye and signed:  _ I have no idea what she’s saying.  _

“Sensei,” Sakura snapped, batting at his hands. “I can see you.”

Sakura had taken some samples of Naruto’s blood and added some sort of dye to them, and apparently the resulting staining pattern had been unusual. Sasuke did not understand half the words Sakura was using to describe it, but he got that it was weird. 

“It means Naruto’s being changed at a cellular level,” Sakura said. “I should take a skin sample, and a sample of that black sludge, and-- oh! I wonder if his demonic arms are different from his normal ones--”

“Sakura,” Kakashi interrupted her. “Maybe you should take a break.”

Kakashi reassessed Naruto’s current seal situation, dubbed him okay to leave alone for thirty minutes, and then went to have a bizarrely surreal dinner together. 

Sakura and Kakashi, with Sasuke, in a Sound hideout. Very weird. He almost missed Naruto’s loud commentary, as it would have at least distracted from the weirdness. 

The kitchen had a metal table with built-in benches, and the three of them ate there. 

“Ah, this is really nice,” Sakura said, cracking a smile as Sasuke unceremoniously dumped food on a plate for her. “Much better than my homemade ration bars.”

Sasuke and Kakashi shared a look. Sakura’s homemade ration bars supposedly offered a better array of nutrients than the store-bought kind, but they also tasted like cardboard. Sasuke was convinced that Sakura had somehow fried all her tastebuds since becoming a medic. 

Still, he was unreasonably proud of the happy little noises she made as she ate. 

“Should we try to feed Naruto?” Sasuke asked while Kakashi washed dishes and Sakura packed up their leftover food. 

“Hmm,” Sakura answered. “I’m worried about him choking, with that weird sludge and all the thrashing around… If we find the equipment, I’d rather set up a nutrient drip.”

There was definitely a clinic, somewhere in the base. Sasuke could even begin to identify what Sakura would need from it, so they put it on the backburner, for her to explore herself later. 

First, she wanted to try out a chakra separation technique.

“This is modified from a surgery we use sometimes with high-risk pregnancies,” Sakura said, positioning her hands over a test tube of Naruto’s blood. “Supposedly, Nidaime-sama originally developed it in response to a fuuinjutsu accident.”

Sasuke activated his sharingan to watch her. Blood, according to Sakura, was the ideal tissue to test her wild experimental surgery out on, because it was infused with chakra directly from the heart. 

_ The ideal tissue to test  _ sounded exactly like something Orochimaru would say, and it made the hairs on the back of Sasuke’s neck stand up, even if Sakura was… well, smiley and pink and polite, and not a creepy snake person. 

_ (Sasuke _ was, technically speaking, his own brand of creepy snake person.)

Slowly, Sakura’s medic chakra poked at the chakra in Naruto’s blood, sorting out the corrupted chakra and diffusing it harmlessly into the air. It took three hours of intense concentration, but Sasuke was pretty sure what she was doing would be impossible for all but a handful of other shinobi. 

When Sakura was done, she stepped back and wiped sweat from her brow. 

“Well,” she said, breaking the silence. “It technically worked.”

“What’s the issue?” Kakashi asked. 

“If I do it on Naruto, it’ll take  _ much _ more time and chakra, especially since the temple seal will be sucking up my chakra too,” Sakura said. “On top of that, I might have to undo the physical effects of the corrupted chakra. Without an assistant, I’ll need to use Mitotic Regeneration.”

Kakashi pinched the bridge of his nose, then turned to Sasuke. “An assistant… Can you copy medical techniques, Sasuke?”

“No,” Sasuke answered flatly. Medical ninjutsu took an absurd amount of precise chakra control. He could see how they worked, but he didn’t have the control or background knowledge to do them himself. 

“Yeah, I couldn’t either,” Kakashi answered, then sighed deeply. 

“I’m alright with using Mitotic Regeneration,” Sakura said. “It’s for Naruto.” 

“I know,” Kakashi said, rubbing the back of his neck. “But you know Naruto wouldn’t want you to, unless it was absolutely necessary.”

Sakura stared down at her hands. Sasuke had been away from Team Seven for a while, but even he understood that Naruto would be hurt if his dumb mistake in the temple ended with Sakura shaving years off her lifespan. 

“Here’s what we’re doing,” Kakashi decided, and Sakura straightened up, a good shinobi taking orders from her captain. Sasuke made himself straighten up too, but not after a few moments of hesitation. 

Kakashi gave his orders in the curt, direct way he talked when he was being a proper shinobi, which was essentially the opposite of how he behaved socially. The wild experimental surgery was to be treated as an emergency solution only, but an emergency that had a high chance of occurring. Sakura was to prepare like she might need to do the surgery at the drop of the hat; Kakashi and Sasuke would share guard duty so she could get a full night’s sleep. In the morning, when they were more well-rested, they’d reassess and look for an alternative solution. 

Sasuke had absolutely no further ideas for an alternative solution, since apparently  _ do a science _ was much more complicated than he’d anticipated. 

He led his teammates further into the base, to find actual beds. If they were crashing in a Sound hideout, they might as well make the best of it. 

There were a few small bedrooms with their own closet-sized bathrooms, for Orochimaru’s favored shinobi. Sasuke dropped Kakashi off in the only one that had both electricity and running water. He left Sakura in Orochimaru’s own room, since it was the most comfortable and had a full-sized bed. 

She hesitated at the door. 

“The sheets should be clean,” he told her. It was protocol. When Sakura took two steps into the room and stopped, he added, “You’re okay with using his lab. It’s not like he did anything evil in bed.”

Sakura turned to him, her lips twitching upward. “Yeah?” she said. “Not into  _ evil in bed, _ was he?” She dropped her pack onto the bed and started rummaging around in it. When Sasuke didn’t answer her, she prompted again, “No  _ evil kinks?” _

“...Are you asking me about Orochimaru’s sex life?” Sasuke asked. 

Sakura retrieved a toothbrush from her bag and shrugged. “You’ve never thought about it? The  _ tongue--” _

Sasuke closed the door on her. Karin and Suigetsu debated this exact subject, sometimes, and it always ended poorly. 

Sasuke headed back to the lab, so he could watch over Naruto and make sure he didn’t get loose or hurt himself. The lab needed exhausts into the open air, so it was near the entrance to the hideout, and Sasuke would also be able to monitor if any enemy ninja were stupid enough to stumble in. 

When he got to the door to the lab, there was a little sparrow hopping around the hallway. Sasuke caught it easily, and gently pulled a tiny roll of paper off its leg. 

_ We’re close. Be there soon, _ it said in Juugo’s neat handwriting. 

Sasuke settled in to watch Naruto, the note in hand. He’d alert Kakashi to this development when he went to wake him up and trade-off guard duty at 2AM. He hoped Kakashi felt the same little flicker of relief about the arrival of Team Taka that Sasuke did. 


	2. Day 2

**Summary for the Chapter:**

> Team Taka shows up, Sasuke loses all control over the situation, and there are more pipette tip jokes than anyone has ever asked for, ever.

**Notes for the Chapter:**

> I do NOT know how this got so long. :(
> 
> Also! It may be helpful to look at this picture of a pipet tip box: https://previews.123rf.com/images/butaiump/butaiump1707/butaiump170700002/83029840-fill-the-pipette-tip-to-a-tip-box-isolated-on-white.jpg (you will have to copy+paste because AO3 did N O T like this link)

Team Taka showed up at dawn, while Kakashi was on Naruto Watch. Sasuke walked into lab to find Karin in an in-depth discussion with Kakashi about the merits of  _ Icha Icha Paradise _ versus the knock-off parody  _ Icha Icha Parasite.  _

“The sex scenes in  _ Parasite _ are definitely better, even if the science is shit,” Karin was saying. “You can tell the writer has, like, actually seen a woman orgasm.” 

“Maa, but the romance isn’t as good,” Kakashi countered. “I’m a man who needs to be wooed.”

“What’s up?” Suigetsu greeted Sasuke. “You were  _ not _ kidding when you said your old teammate was, uh, having problems.”

Naruto was currently caught in a miasma of dark chakra. He had stopped trying to scream through his gag, as Juugo was hovering over him and chanting soothing affirmations at him. 

“Hey, Juugo,” Sasuke greeted. Juugo waved back. 

“Eh?” Karin asked, leaning into Kakashi. “Do you need a demonstration, Hokage-samaaa~?”

Sasuke had missed what Karin wanted to demonstrate, but the way she dragged out the honorific definitely meant Kakashi was either going to die or be seduced. Sasuke couldn’t decide which was worse. He moved to intervene. 

“I’m not quite Hokage yet,” Kakashi answered, although he made no move to back away from Karin as she very unsubtly cozied up to him. 

Okay,  _ this _ was the worse option, Sasuke decided, feeling something in his brain break. Karin trying to assassinate a world leader was something he could deal with. Not her… flirting… Kakashi was his _ teacher. _ Karin was his  _ teammate. _ This was the worst possible way for his two worlds to collide. They weren’t supposed to… not… no. 

_ No.  _

“Karin,” Sasuke greeted. “You look good. I like the haircut.” 

There. Karin always got distracted when he complimented her appearance. 

“Pfft,” Karin answered, flipping said hair over her shoulder and thankfully backing off from Kakashi. She’d shaved off one side of her hair, but the rest of it was longer than she’d ever kept it. “You’re damn right I look good, Sasuke-kun. Where’s your teammate that actually knows what she’s doing?”

“You know where she is,” Sasuke said. Karin always knew where everyone was. 

“Yeah,” Karin answered, brushing by him and bumping him with her hip unnecessarily as she moved to the lab bench, “I do.”

Sakura was still in Orochimaru’s room, but Sasuke pointed Karin at her notes and tried to walk her through what they’d done the day before. 

“Aaw,” Karin cooed, interrupting him as he spoke. “You don’t have any clue, do you?”

“He tried to use the pipette without a tip,” Sakura said from behind Sasuke, having just staggered into lab. She sounded tired. Sasuke twitched. 

“Oh,  _ Sasuke-kun,” _ Karin sighed. There was a laugh behind it. Sasuke twitched some more. 

“He wasn’t completely useless,” Sakura said, obviously fighting back a yawn. “He helped me figure out the current situation with Naruto’s chakra.”

“Okay, walk me through it,” Karin said to Sakura, then turned to Sasuke and added, “and why don’t  _ you… _ go find us some breakfast?”

“With coffee,” Sakura said. 

“With coffee,” Karin agreed. “And sweetened condensed milk.”

Sasuke twitched some more, but it wasn’t like he had anything better to contribute. He turned and marched out of the lab. 

“Oh, like the dessert coffee they have in Water Country?” Sakura was asking Karin as Sasuke left. 

“Yeah, have you tried it? It’s really good. What type of chakra isolation method are you using for…” 

Suigetsu followed Sasuke out of the lab, having dropped his travel pack and sword off in a corner. 

“Were you ever stationed here?” Suigetsu asked. Sasuke grunted out a negative. “I was here for like a month. Probably the worst of the hideouts-- the water has way too much calcium.”

Suigetsu was the source of Karin’s addiction to Water Country-style coffees (although she would deny it vehemently if anyone brought it up), so Sasuke let him prepare coffee while he tried to figure out a meal from the random assortment of canned goods still in storage. He ended up cooking up powdered egg and canned tomatoes with the rice from the day before. He also threw in plenty of spices because he was… dubious about the flavor of powdered egg. 

He and Suigetsu brought plates of food back into lab, and Sakura gave him a look like he’d tracked dog shit into her house. 

When Sakura started on what was sure to be a long lecture (the type she’s give  _ Naruto), _ Karin interrupted: “Yeah, Sasuke-kun, Suigetsu. You could contaminate our experiment.”

“The  _ experiment--” _ Sakura half-shrieked. “They could ingest  _ hazardous chemicals--” _

Sasuke had definitely seen people eating in Sound’s labs before. He sensed this would be a bad thing to point out to Sakura, as she looked like she was on a brink of throwing fists. 

“We don’t  _ have _ anything that would do damage you couldn’t reverse easily,” Karin reasoned, patting Sakura on the shoulder. “How about we just keep them away from chemical storage, and then we can all talk while you show me your slides.”

Sakura still looked unhappy. 

“We could eat in the biosafety cabinets,” Suigetsu offered, having carefully set both trays of food he had down on the floor, which was likely the most contaminated area. “Those are sterile, right?”

Karin declared Suigetsu the dumbest person on Earth, Suigetsu informed her she was a heinous bitch, and Karin  _ actually _ attempted to throw fists. Sakura yelped and threw her arms around Karin to pull her back. 

“Aw,” Kakashi said to Sasuke, watching Sakura wrestle Karin away from Suigetsu. “Just like when you were twelve.”

“Yeah,” Suigetsu goaded, “Karin, you’re just like a  _ child.” _

Sakura twirled and grabbed Suigetsu by the neck. 

“You,” she hissed, “are  _ not  _ helping.”

Suigetsu shut up. Karin looked smug as Sakura grabbed two plates of eggs and muttered, “C’mon, Karin, we can do actual work.”

Karin continued to look smug as she took two mugs of coffee from Sasuke's tray and sauntered off after Sakura.

Sasuke plopped down on the floor, his knee brushing Juugo’s, and pulled a plate to himself. Naruto jerked and glared at him, but wasn’t screaming nearly as much as before.

“This is pretty good,” Kakashi said over his own plate. “You always had the best culinary talent, my cute student.”

Sasuke grunted, focusing on making sure every bite had at least one piece of tomato in it. The egg tasted fine, but the texture was weird. Tomatoes usually solved all flavor problems, in Sasuke’s opinion. 

“Are we going to feed him?” Juugo asked, sending a worried look over at Naruto. 

“Our medic was worried about the demonic seizures making him choke,” Kakashi answered. “She’s going to try an intravenous feeding today.” 

“It’s actually good the tomatoes aren’t fresh,” Suigetsu said, very authoritatively. “Local tomatoes would be filled with the horrible local water and taste bad.”

Sasuke was unsure if this was true. He was sure Karin or Sakura would know about how water taken but from soil affected the taste of fruit, but they were busy huddling around a microscope and giggling. For some reason, this made Sasuke deeply nervous. 

When they were finishing up eating, the giggling was still happening, and they’d done none of the discussion-over-breakfast Karin had suggested.

“I’m going to go check on them,” Sasuke announced, setting aside his empty plate. Juugo had volunteered for clean-up duty.

“Yeah, they might need you to go make some more snacks,” Suigetsu snorted. Sasuke shoved him lightly as he passed. 

Sasuke’s nostalgia for Team taka had mostly just been reliving memories of how  _ supportive _ and  _ respectful of his leadership _ they were. He may not have been thinking about some very important details, such as his  _ entire team’s personalities.  _

Sakura had refused to let Karin have food or drink at the actual lab bench (“What kind of lab safety was Orochimaru _ teaching _ you?”), but the microscopes were on a separate desk and she’d caved to eating breakfast there while she showed off the slides she’d made. 

“Eh?” Karin asked, leafing through Sakura’s notes. “Why did you  _ sign _ this, Haruno?”

“What if someone finds those,” Sakura stammered, her cheeks turning pink, “and has questions about what I did? It’s just protocol!”

“You’d make a horrible renegade ninja,” Karin answered. She smirked up at Sakura, running her foot down the back of Sakura’s calf while Sakura’s cheeks went from pink to bright red. “All concerned about protocol and policy…”

“Ah, you’re in quite the conundrum,” Kakashi sighed into Sasuke’s ear, having snuck up behind him like the creep he was. “Two beautiful, intelligent women once in love with you, now setting their eyes on each other… you know, this is the plot to my favorite  _ Icha Icha--” _

“Shut  _ up, _ you weird pervert,” Sasuke snapped, shoving Kakashi away. 

“Oh, S-sensei, Sasuke-kun,” Sakura said, turning in her chair. She seemed flustered for some reason. Karin continued to smirk, resting her chin in her hand. “Karin thinks Kakashi’s seal modification worked and the contaminated chakra has stabilized. That is, it’s not infecting any more of Naruto’s or the Kyuubi’s chakra than it was when she first got here.”

“That’s good,” Kakashi said. To Karin he asked, “Do you have any ideas for fixing it, besides wild experimental surgery?”

Karin shrugged. “Not really,” she said. “Most of my lab experience is in genetic manipulation.”

Kakashi’s shoulders slumped ever so slightly. 

_ “But,” _ Karin continued, “I have enough medical training I can assist in the wild experimental surgery, if it comes to that.”

By “medical training” Karin almost definitely meant that, quite early in her career in Sound, she’d cottoned onto the fact that assisting in Orochimaru and Kabuto’s own wild experimental surgeries meant she didn’t have to be the  _ subject _ of said surgeries. She was clever and dexterous and had proficient enough chakra control that it was a strategy that had worked out quite well for her. 

“That makes it safer, right?” Sasuke confirmed. 

“Mm,” Karin replied. “Sakura won’t have to use weird regeneration techniques, and neither will I. Win-win.”

Sakura bit her nail. “It’s still dangerous. We won’t know what the Kyuubi will do if we mess with his chakra, or how Naruto’s body or the temple seal will react, and we have no back-up if something goes wrong.”

“I can restrain the Kyuubi,” Sasuke promised. Karin could too, probably, but not necessarily while also doing surgery. 

Karin shifted slightly, leaning back on her elbows against the desk and knocking her knee against Sakura’s. 

“The problem there is less that the Kyuubi could go on a rampage,” she said, “and more that if its chakra goes nuts, it could take out your only proper medic.”

“It’s a risk I’m willing to take,” Sakura said grimly. “Both Karin and I have ways to bring me back from the brink of death.”

Karin’s face was carefully neutral as Sakura spoke. Part of Sasuke wanted to object-- he didn’t like Sakura  _ volunteering _ Karin’s healing ability up like that. But he was also sure that Karin must have volunteered this talent to Sakura herself; it was something Karin kept close to her heart, and Sakura wouldn’t have known about it otherwise. 

Sakura saved Karin’s life once, Sasuke remembered with a wince. Karin’s sense of justice wouldn’t let Sakura die. 

“But neither of you want to use those ways, and Naruto is stable for now,” Kakashi summarized. “I think it’s better if you two work on a safer way to do the surgery, and the rest of us try and figure out something with the temple seal.”

“Very Hokage-like, Sensei,” Sakura answered cheekily, breaking the tension. Karin let out a huff of laughter. 

“I’ve still got two months of freedom before my inauguration,” Kakashi answered lazily. “Let me be a normal team captain in peace.”

Karin, being both someone familiar with Sound and a sort-of medic, took Sakura to figure out if they had the equipment and supplies to set up a nutrient drip on Naruto. That left the rest of them to try to sort through the various lab notes and random scrolls to try and find something useful. Suigetsu and Juugo both went off to see if there were more scrolls or books scattered around the hideout, leaving Sasuke and Kakashi alone with the lab’s collection and their possessed teammate. 

Sasuke started on one of the binders, which was filled with print outs of… readings of… something. There were graphs. He knew what an X-axis and a Y-axis were and understood that the X-axis was labeled “time.” The Y-axis was mysteriously labeled “OD” and there was no explanation for this anywhere, or any indication of what the experiment even was. 

Sasuke tossed the notebook aside, into what Sakura had started as the “useless” pile when she’s been looking for a protocol book. He went for a lab notebook next. This contained actual words, along with some scribbles of jutsu formulations that were basically nonsense to Sasuke. 

Not for the first time on this mission from hell, Sasuke felt essentially useless. It was never a feeling he was very good at dealing with, and it clawed away at his stomach. Why weren’t more problems solvable by lighting them on fire?

At least Kakashi was easy to work with. He wasn’t one to be unnecessarily chatty, or to confront Sasuke on his feelings. 

That was right up until Kakashi decided to betray him and start a conversation. 

“You know,” Kakashi said, dropping another notebook into the useless pile. “I spend most of my time comfortable with my knowledge of fuuinjutsu, right up until those days where I  _ deeply _ regret not asking Minato-sensei for more lessons when I could.”

Sasuke made no noise of acknowledgement. This was more or less exactly how he was feeling about his lack of science lessons and medical training right now, but  _ screw _ Kakashi if he thought he could trick Sasuke into a heart-to-heart. 

“This is one of those days,” Kakashi said helpfully. 

“I got that,” Sasuke sneered back. 

“If only more problems could be solved by electrocuting them,” Kakashi continued, unabashed. 

“Uh-huh,” Sasuke said, focusing very hard on a jutsu formula for… something to do with reversing the flow of blood. Why? What would be the point of that? 

“Maa, your team is interesting, though.” Kakashi knelt to rip a page out of one of the useless binders and bookmark something. “T&I is still yelling about the redhead.”

“Karin,” Sasuke corrected. 

“And-- did you take the Hoozuki to Zabuza’s grave?”

“Something like that,” Sasuke said. Desperate to change the topic of conversation, he held out the notebook. It contained two very mysterious jutsu formulas. “What does this mean?”

Kakashi skimmed the page. 

“Sasuke,” he said slowly, “what’s your background in fuuinjutsu?”

Sasuke felt more twitches coming on. He might have to get that checked out, when this was all over. 

“I know the basics of my old Cursed Seal,” he admitted, “I can make simple storage seals.”

Kakashi politely suggested Sasuke go get organized for lunch. Sasuke did  _ not  _ throw the notebook at him before he stomped out of the lab, because Sasuke was a mature adult now. He passed Karin and Sakura in the hall. 

“Hey,” Karin said, snagging his sleeve, “we’re gonna move Naruto into the clinic. Wanna help?”

This, at least, Sasuke could do. 

After they’d tied Naruto down to an examination table (“ **CRAWL, PATHETIC CREATURES, AND BEG FOR MERCY,** ” Naruto screamed when his gag slipped), Sakura managed to stick a line in him. Then she assigned Sasuke to be his guard until someone else was free. 

“If he pulls out the line…” Sakura started, frowning slightly down at Naruto’s twitching figure. “Well, he’ll be fine for a while. Leave it.”

Sasuke slumped down into a swivel chair and glared at Naruto. Naruto’s eyes were completely glazed over obsidian, and so it was unclear if Naruto was glaring back. He did, however, continue to try and scream obscenities through his gag. 

“Hey,” Sasuke said, reaching forward with one leg to kick Naruto’s weird hooved demon feet, “fuck you.”

_ Fuck _ Naruto indeed, for getting into this mess, and for making Sasuke care enough to stick around and try and solve it. And  _ fuck _ Naruto for having enough interest in fuuinjutsu that even he’d be less useless than Sasuke in this situation, if their roles were reversed. 

It felt like being thirteen again, and being convinced everyone was leaving Sasuke behind and he was a useless failure, except now Sasuke was a full grown adult and he was going to be  _ cool and mature about it, okay. _ He’d saved the lives of every single person on both his teams at least once. They all valued and respected him. It was  _ okay _ that he couldn’t take the lead on this one. 

Cooking was totally a valuable contribution to the team, anyway. Sasuke mentally reminded himself of this several times, crossing his arms and glaring at Naruto. Naruto couldn’t cook. Even Sakura and Kakashi were minor disasters in the kitchen. It was fine if this was Sasuke’s major contribution-- everyone needed to eat, after all. 

(Sasuke still wanted to be the one actively saving Naruto.)

Suigetsu wandered in an hour later and made a grabbing motion at Naruto’s head. 

“Hey,” Sasuke said, sticking an arm out to intervene. “What are you doing?”

“Getting a DNA sample,” Suigetsu said, trying and failing to push Sasuke out of the way. “C’mon, I just want a few hairs.”

“A DNA sample for what?” Sasuke asked. Sakura had already taken a blood sample. If she wanted DNA, she’d just use that.

“He’s an Uzumaki, right?” Suigetsu said. “I’m gonna see how related he is to Karin.”

_ “Why?” _ Sasuke asked, physically grabbing Suigetsu’s wrist as he made another bid to rip out Naruto’s hair. 

“Everyone else is doing fun science experiments,” Suigetsu whined. “And the DNA machine is the only thing I know how to use.”

The DNA machine…?

“It goes  _ ding _ when there’s a match,” Suigetsu explained helpfully at Sasuke’s confused face. 

“I don’t think you should be doing something like that without Karin or Naruto knowing,” Sasuke settled on finally. After the Uchiha Massacre, there had been quite a few people coming forward and claiming to be illegitimate Uchiha for various reasons, all of which were deeply upsetting to Sasuke. 

None of them had been actual Uchiha, but Sasuke had gotten a crash course in how DNA tests for inheritance could make people lose their  _ minds. _

“God, you sound like my auntie when Mangetsu was convinced his girlfriend was cheating,” Suigetsu said, rolling his eyes but backing off. 

“...what?” Sasuke asked. 

“The kid wasn’t his,” Suigetsu clarified, as if this were Sasuke’s question about what he’d just said. “Little bastard got out of the bloodline purge and everything.”

Sasuke considered saying more. Suigetsu’s survival of the Bloody Mist’s clan purges was the closest that Sasuke had ever found to his own trauma. They’d never had a real conversation about it, beyond Suigetsu occasionally making disturbing, flippant comments, but Sasuke had always felt it was a sort of Unspoken Bond, like he’d had with Naruto before he’d tried to break. 

He should say something. 

_...Or _ he could just tell Suigetsu it was his turn to watch Naruto and go back to the lab to see how the “fun science experiments” were going.

“But if your clan is  _ actually _ descended from wolves,” Karin was yelling across the lab, currently arm deep in pipet tips, “we could just test you against one of your dogs and see if it’s true!”

“But aren’t I all the more mysterious without you experimenting on me?” Kakashi asked, casually turning the page in a notebook. They were on opposite sides of the lab, and thus both yelling to be heard. 

Sakura looked up from very sternly pipetting some things across a handful of different tubes. 

“He’s not,” she said, sounding tired. “I checked.”

Kakashi nearly dropped the notebook. “I-- Sakura-chan,  _ when?” _

“I don’t know, years ago,” Sakura said, projecting her voice so everyone in the lab could hear. She went back pipetting. “I was young and dumb and Pakkun convinced me he was your biological uncle.”

There was no way Karin knew who Pakkun was, but the story still made her cackle. It was abruptly cut off by a string of nasty swears. 

_ “Why _ are  _ all _ of these tips melted shut?” Karin growled, hurling an offending box into the trash with unnecessary violence. “What fucking company makes these? I’m never ordering from them again.”

Since Karin was the closest in the lab, and also seemed focused on the least important task, Sasuke went to her to ask for updates. 

“Well, Hokage-sama over there has found nothing,” Karin said, pulling another box of tips forward and stabbing a pipet into it, “and Sakura and I found a bunch of old samples in the one working freezer that are probably still good.”

“Are they helpful samples?” Sasuke asked. 

“Not all at,” Karin answered. “But I told Sakura we found IL-4 transcripts in some of the frozen EVs and she’s determined to show me the protein is in there too.”

That was… Sasuke didn’t even know how to begin breaking down how little of that he understood. He was familiar with what a protein was. And, like, the concept of freezing. 

“I don’t see how that’s useful to Naruto,” he said. 

Karin just raised her eyebrows at him. “Oh, it’s  _ absolutely _ not. Your teammate is stress-blotting.”

Sasuke stared at her. 

“The stress is making her freak out and make a bunch of Western blots,” Karin clarified. Sasuke twitched. “She’s grasping at straws for something she can control. She’s  _ stress-scienceing, _ Sasuke-kun.”

“Better than when she stress-bakes,” Kakashi called from across the room, then had to dodge a box of faulty pipet tips Sakura threw at him. “Speaking of food, Sasuke, my cute little chef…”

Sasuke retreated to the kitchen in a foul mood. He put extra chili flakes in Kakashi’s portion. 

It wasn’t technically a political assassination if he killed the Hokage-elect for personal reasons, right?

When Sasuke went back to the lab to tell them lunch was ready, Sakura had her face planted in Karin’s back and was whimpering while Karin pipetted liquid into a strange contraption. It looked like she was making… some sort of transparent, gooey sheet.

“No,  _ shh, _ everyone gets bubbles in their gels sometimes,” Karin cooed. “You’re still the best medic in the world.”

“My blot,” Sakura whined. “How am I supposed to save Naruto if I can’t even make a blot?”

Sasuke  _ still _ didn’t know what a blot was. 

Karin set aside the now empty flask and turned around to pull Sakura into a hug. She rotated her wrists outward, so her gloved hands didn’t actually touch Sakura. “I’ve got you. See? No bubbles!”

“One of your hairs is in it,” Sakura sniffed. 

_ “Fuck.” _

Suigetsu shuffled over to Sasuke, several golden hairs in his fist. 

“I do  _ not _ know what’s going on anymore,” he said. “But look! The demon in your teammate said I could do whatever I wanted with his mortal coil!”

“That’s not--” Sasuke started. “You  _ talked _ to it?”

“Well, Juugo did,” Suigetsu said. “He was pretty clear about not caring what happened to the physical body.”

It took some prompting to drag Sakura away from the lab to eat. Karin stayed behind, promising with great determination that she would make the perfect gel for Sakura. 

“It’s for electrophoresis,” Suigetsu said very knowledgeably. “I spent a lot of time in the lab, you know. Learned some stuff.”

“What did you do?” Kakashi asked with genuine curiosity, his hands on Sakura’s shoulders. Sakura had one of her hands over his, so it was obviously a comforting gesture. 

“Uh,” said Suigetsu, who spent most of his lab time as an experimental subject and definitely didn’t know what electrophoresis actually was. “Nevermind…”

Lunch consisted of tinned fish, more canned vegetables, and some dehydrated shrimp that Sasuke cooked in a coconut-based soup. 

“This is really good,” Sakura said, smiling weakly at him. “Thanks, Sasuke-kun. I feel better.”

Sasuke didn’t know how to respond to that, so he just shoveled more soup into his mouth and prayed he wasn’t blushing. Sasuke did  _ not _ blush.

Lunch was interrupted a few minutes later by Karin bursting into the kitchen in a panic. 

“Fuck!” she yelled. “Shit! Shit fuck!”

“Did you get more hair in your science project?” Kakashi asked, eyebrows raised. 

“Did you inhale acrylamide and endanger your neural functions?” Suigetsu asked with the air of someone who had definitely heard those words before and did not know what they meant.

“No!” Karin snapped at him. “Orochimaru is coming. He’ll be here in a few minutes.”

_ Thank god, _ Sasuke thought.  _ Finally, a problem I can electrocute.  _

Orochimaru probably would have waited until morning so that they could find him sitting on a bench in the lab, leaving them all vaguely paranoid he’d been watching them in their sleep, or at least something similarly dramatic. It was, however, nearly impossible to sneak up on Karin while she was awake, even for Orochimaru. 

Suigetsu both feared and hated Orochimaru more than the rest of Team Taka, so they left him with Sakura and Naruto while the rest went outside to meet Orochimaru. Kakashi was obviously tense-- his posture was  _ never _ that good when he was relaxed-- but neither Sasuke nor Karin nor Juugo were particularly nervous. 

(Karin and Juugo, after all, both felt they’d fared better under Orochimaru’s care then their own villages. Sasuke… well, Sasuke’s teenage years were complicated.)

“My, my,” Orochimaru crooned, strolling out of the forest and into view as casually as if he’d happened upon them on a normal midday walk. “Joining your teams together, Sasuke-kun? Or is it just Kakashi-kun today?”

“How did you know we were here?” Sasuke asked, cutting right to the chase. It was always dangerous to let Orochimaru get off task. He liked to poke and prod at his distractions a little too much. 

“Snakes gossip,” Orochimaru said, eyes crinkling at a devastatingly creepy smile that made Kakashi tense up even more, his spine going ramrod straight. Of course, this just made Orochimaru turn his smile to Kakashi. “I am honored to have the new Hokage staying in my home.”

“It looks like you haven’t been home in a long while,” Kakashi replied. 

“I haven’t,” Orochimaru said, pushing a loose strand of hair behind an ear. “But I heard the most  _ fascinating _ rumor about a problem one of my old students was having, and I thought I’d see if he needed help.”

“Ooh,  _ help?” _ Karin repeated, matching Orochimaru’s crooning tone. “From  _ sensei?” _

“What kind of help?” Kakashi asked, ignoring her. His posture was still rigid, but his voice sounded more resigned than confrontational. 

“I’m always willing to help my old students,” Orochimaru said, “especially when their problems are… unique.”

“Unique is one way to put it,” Kakashi said, crossing his arms. 

There was a lot more back and forth between Kakashi and Orochimaru, but at the end of the day, they were desperate to help Naruto, and Orochimaru was one of the few people out there who could bring more expertise to the table than the team they already had. It also helped that Orochimaru was here, right now, and not in another village. 

“If you try anything,” Sasuke said, “if you put one toe even a centimeter out of line, I will kill you.”

He could do it, too. He’d done it before, and now he had like. Fifteen types of magic eye powers  _ and _ the immortal soul of demi-god. 

“Sasuke-kun, I’m not a  _ monster,” _ Orochimaru chided. Juugo winced and Karin choked back laughter. “Show me your little problem and I’ll see what I can do.”

Kakashi led the way, and Karin fell into step beside Orochimaru as they walked through the base, just as if she were still a loyal Sound-nin reporting in to her boss. She filled him in on the technical details of the problem, and what they’d done so far to fix it. 

When Orochimaru stepped into the room, Sakura immediately stepped between him and her patient. 

“What the  _ fuck  _ is this?” she asked, turning her glare to Sasuke like this was somehow his fault. 

“Sakura,” Kakashi cut in, moving to her side, “we’re not going to get any better help than his. Sasuke can handle him.”

Sakura, still glaring as fiercely as Sasuke had ever seen, eyed Orochimaru up, from foot to head. Orochimaru just smiled pleasantly back at her. 

“I’m looking forward to working with Tsunade-hime’s apprentice,” he said. 

There was a long, tense silence, and then Sakura’s face melted into her own pleasant smile. Next to Sasuke, Karin suddenly sucked in a lot of air. 

“She spoke very highly of your analytical brain,” Sakura said. With her polite tone and extremely pleasant smile still in place, she added, “Step out of line, and I will scramble that brain so bad you won’t even be able to wipe yourself.”

“Oh, Sasuke-kun,” Orochimaru purred as Sakura moved aside, “I  _ like _ her.”

This was, quite possibly, the most nerve-wracking development yet. 

Sasuke caught Karin’s eye, and she waggled her eyebrows and him and fanned herself with a hand. 

“Sensei, Sakura,” Karin called, still eyeing Sasuke meaningly, “I’m going to go finish something in the lab. Sasuke-kun, come with?”

As they were stepping into the hallway, someone pulled the gag out and Naruto screamed,  **“YOU WILL CHOKE ON YOUR OWN BLOOD AS THE WOLVES TEAR OUT YOUR INTESTINES.”**

“No, shh, remember your breathing,” Juugo said in his most soothing tone. 

“Fascinating,” Orochimaru said. 

As their voices faded, Karin looped her arm through Sasuke’s and said, “Did you _ see _ the way she smiled when she did that?”

“Sakura?” Sasuke asked. 

“You should have  _ felt _ her chakra,” Karin gushed. “Perfect, lovely face, and then chakra like a  _ storm-- _ like, like, Sasuke-kun, did you know your teammate could perfectly hide killing intent? Like, a  _ huge _ amount of killing intent, all coiled up and hot and heavy--”

Karin continued to babble, her walk turning into more of an excited skip as she dragged him along. Sasuke had only really seen her get like this about Team Taka’s sleeping arrangements, or that time he’d had to take off his shirt after a training accident. 

Sasuke had seen Sakura smile like that before. She used it almost constantly in the Academy, and then when they were genin. She’d definitely turned that smile on  _ him  _ a few times. He hadn’t realized it was hiding killing intent. 

_ How many times did I nearly die? _ Sasuke wondered. 

Karin hummed as she went back to trying to fix Sakura’s… stress-blot, or whatever it was. 

Notably, she pulled her hair back into a ponytail to keep it out of the way. 

“Do me a favor,” Karin said, picking up a tube mysteriously wrapped in tin foil, “and try and find P200 tips that work, will you?”

Sakura had not explained this to him, but Sasuke had noticed the tops of the pipettes were labeled with numbers, and one of them was P200. He did not know what this secret code meant, but he did locate a box of pipette tips that fit it. 

The bottoms of the tips-- the narrowest part, which took up liquid-- were all melted shut. Huh. 

“Is this a normal problem to have?” Sasuke asked, when he finally found a box of tips that worked. 

“Not really,” Karin called back as she pulled some things out of the freezer. “But remember how I was always complaining about people just ordering the cheapest option?”

Yes, Sasuke remembered. There was probably an entire year of Karin’s life dedicated to screaming about poor record keeping, and how if people read her notes about X product working best, they wouldn’t be having Y problem. 

_ Karin really shines at management, _ Orochimaru had said. 

“Okay,” Karin said, pulling the tip box toward her. She sighed. “Fuck, Western blots have way too many steps. Why did Sakura have to get fixated on this?”

Karin grumbled to herself while she pipetted things together, giving Sasuke the brief explanation that she had to calculate protein concentrations. It involved a lot of tiny tubes and things turning purple. 

“...stoichiometry?” Sasuke asked slowly. 

Karin paused, pipette hovering over a tube in a rack. 

“I guess, technically,” Karin answered after a moment. 

Sasuke wasn’t sure if he’d actually learned something or not. Was this how Suigetsu felt, every day, living in a glorified test tube in the lab? 

No, he probably felt worse, because in addition to not understanding anything, sometimes the experiments happened to  _ him.  _

Sasuke decided to change the subject. 

“You’re really going out of your way for Sakura,” he said, and then winced internally because he sounded exactly like Kakashi trying to have a heart-to-heart with him earlier that morning. Karin transferred all her tiny tubes to a heating block before she answered him.

“Are you going to freak out if I keep hitting on her?” she asked bluntly. 

“Uh,” Sasuke answered. 

“Because unlike with your hot sensei,” Karin continued casually, grabbing a digital timer, “I actually have a shot with her--”

“Please don’t call Kakashi hot,” Sasuke said. 

“Oh, a  _ please,” _ Karin teased, hip checking Sasuke gently as she set the timer back down. “Konoha has been good for you.”

Sasuke was saved from having to come up with a witty comeback because Sakura burst into the room, followed by Orochimaru and Kakashi. 

“No, we  _ made _ the arm,  _ that’s _ not the issue,” she was saying. “He just didn’t want it--”

Sakura froze when she saw Sasuke. He stared back at her. Her face twitched, and then her face shifted into a resolute look that clearly said:  _ Yeah, bitch, I  _ was _ talking about you.  _

Well, okay. Maybe he deserved that. 

“Ah, Sasuke-kun,” Orochimaru greeted. “We were looking for you.”

There was a chalkboard on one wall, and they gathered around it while Orochimaru sketched the seal currently glowing dark purple on Naruto’s chest. 

“This is the current shape of the seal,” Orochimaru started, articulating each syllable clearly as he spoke. It was his  _ I am explaining something to you because I expect you to learn _ voice, which lacked all the silkiness of his  _ I am explaining something to you because I want to watch you try not to cry over it _ voice. The latter was Orochimaru’s preferred method for communicating his research to the subjects of said research, preferably as they were being prepped for surgery. 

Orochimaru pointed to several features of the seal and explained what they likely did, and even Sasuke felt like he sort of understood what was going on. Orochimaru was very good at explanations, even if they made you cry. 

“These parts indicate that the seal has been reduced,” Orochimaru said. Sasuke had no idea how seal reduction actually worked, but he knew the term-- it was how you took a big seal like the Cursed Seal and folded it up into smaller pieces. “I could just unfold it and look, but it might rip poor Naruto-kun to shreds in the process, and I’ve been informed you don’t want that.

“However,” he continued, “Kakashi-kun pointed out that the seal must have been unfolded when it attached to Naruto-kun, and that someone must have seen it through his doujutsu.”

Orochimaru held out the piece of chalk to Sasuke. 

It took a couple of seconds of sorting through his memories, but Sasuke  _ had _ seen the seal through his Sharingan, all unfurled across the temple floor and bright with chakra. He took the chalk with only minor trepidation. 

The seal had been huge, and it took several minutes for Sasuke to sketch it all out. The rest of the group watched him in tense silence, broken only by Karin’s timer going off. She rushed off to mess with her protein samples, and Sasuke sort of wanted her back. Karin was under no illusions about Sasuke being anything more than what he was. 

When he was done, Sasuke stepped back, and Kakashi and Orochimaru both crowded forward. 

“...huh,” Kakashi said finally. 

“Incredible,” Orochimaru drawled out. He said it in a way that meant he was impressed, and usually when Orochimaru was impressed with something, it meant it was either really nasty or completely unsolvable. 

“What is it?” Sakura asked. “None of this looks familiar to me.”

“Ah, it wouldn’t,” Kakashi said. He probably would have said more, but Orochimaru cut him off. 

“I imagine Tsunade-hime could only pass on surgical seals,” he drawled, finger hovering over Sasuke’s drawing to trace the lines without smudging them. “These pre-date Tsunade’s medical ninjutsu. They’re from Uzushio.”

He sounded genuinely excited. This boded poorly for the rest of them. 

Kakashi rubbed his temples, and Sasuke glanced across the lab to see Karin look up from some machine with interest. 

“I wouldn’t suppose your sensei’s wife taught you any of these?” Orochimaru asked, eyes sliding over to Kakashi. 

“No,” Kakashi muttered. “I wouldn’t suppose you’ve ever resurrected an Uzumaki sealing master to learn their jutsu, have you?”

Orochimaru laughed at him. 

“I guess we’ll have to do this the old-fashioned way,” Orochimaru cooed. “Oh, this’ll be  _ fun.” _

Without any care for the rest of them, Orochimaru turned and wandered into the lab, pulling ink sticks and paint brushes from draws as he went. 

“What’s the ‘old fashioned way’?” Sakura asked. Sasuke was relieved that someone else also had no idea what was going on. He was especially relieved it was Sakura, who was one of the smartest people he knew. 

Kakashi sighed. “He’s going to break the seal down and physically try out each part to see what it does, and then try to reverse engineer the whole thing to figure out how the parts work together.” Kakashi paused. “Which, with a seal this size, could take  _ years, _ so I better go help.”

It felt bizarre to watch Kakashi shuffle after Orochimaru with body language that said _earnest_ instead of _charging a_ _Raikiri._ Sakura must have felt similarly, because she blinked after him with a sort of dazed look. 

“What about you?” Sasuke asked her.

“Huh?” Sakura said.

“They’re working on the seal,” Sasuke said. “What are you doing?”

“Oh!” Sakura said, shaking herself. “Right. I was going to see if I could figure out a better way to reverse the physical changes. Oh, Karin, you set it up!”

Sakura practically ran over to whatever weird experiment Karin had set up on the bench. 

“Yeah, and this was way too much work, so you have to take over the rest,” Karin said, although she sounded extremely pleased with herself as she watched Sakura put her nose to the glass of the… small tub of gently bubbling liquid? 

Sasuke had no idea. The goo-sheet was in it. Karin had pipetted blue stuff over the top. 

“Of course,” Sakura said, beaming up at Karin. “Thank you so much, Karin.”

She reached for Karin’s hand, paused over the glove for half a second, and then reached up to grasp Karin’s shoulder. 

Karin’s ears turned as red as her hair. “I-it’s not like it was hard or anything…” she stammered out. 

“Do you want to help me?” Sakura went on. “Suigetsu mentioned you’re an Uzumaki so I understand if you want to help with the seal instead…”

“O-oh,” Karin said, fiddling with her glasses. “Well, my mom only got to teach me a little before… um, well, Orochimaru-sensei analyzed all that… I’m much more comfortable with the biological side, you know.”

“Great!” Sakura said with a grin. “We can start by grabbing some more samples from Naruto.”

While Sakura busied herself grabbing supplies, Sasuke raised his eyebrows at Karin. 

_ Smooth, _ he mouthed at her. 

Karin blushed furiously and flipped him off. 

She made him mangekyou Naruto into submission while she and Sakura scraped things off Naruto and poked him with needles. It was careful, methodical work, and Juugo watched over them with a worried look on his face. 

“Oh my god,” Karin said to him after he hovered a little bit too close. “Juugo, we’re not  _ hurting _ him.”

“I know, but…” Juugo said. Juugo wasn’t one to fidget, but he looked like he might start at any second. “He’s afraid of needles.”

“Who, Naruto?” Sakura guffawed. “He won’t even remember.”

Juugo was happy to keep watching over Naruto, so after replacing his restraints, Karin assigned Sasuke to sort through all the pipette tips and toss the ones that melted shut. She made a joke that ended, “ _...just the tips,” _ which Sasuke didn’t get but made Sakura burst into hysterical giggles. 

Prepping the samples involved a lot of pipetting things together and then onto microscope slides. It was apparently a pretty mindless task, because Sakura and Karin started chatting pretty quickly. 

“Orochimaru said you did some work with Hashirama cells,” Sakura said. “We made Naruto’s arm out of them, but about 90% of that research was already done by someone else, so I don’t really know very much…”

“Oh, yeah, they’re super annoying to work with,” Karin said. She very casually pulled a bottle of nail polish out of a drawer and added, “Do you want me to seal the finished ones?”

Sakura passed over several slides, which she’d covered with a tiny plastic square so the sample didn’t drip off. Sasuke watched in fascination as Karin glued the square in place with nail polish. 

Karin kept talking about her battle against Hashirama cells: “Basically, it’s super easy to get them to differentiate into new cell types, but then most of the time you don’t get what you want. And when you do, they like to kill whoever you graft them onto.”

“Oh yeah,” Sakura said, nodding along as she sorted slides. Some of them weren’t going to Karin to seal shut, and Sasuke wondered about that briefly before remembering he had his own task to focus on. “Currently, we have to use all these weird seals to keep the arm from attacking Naruto. That’s why it has to stay bandaged.”

Karin looked up at that, nail polish brush in hand. “And they didn’t interact with the new, crazy seal?”

Sakura shrugged. “That’s why I took a bunch of samples from the Hashirama arm.”

Sasuke wasn’t one to feel the need to participate in conversations. Mostly, he didn’t care enough about other people to want their attention. But he did like both Sakura and Karin, even if in his mind they lived in entirely separate worlds, and it was messing with his head that they were both somehow getting along independent of him.

That is to say, Sasuke thought it was completely internally consistent when he decided to speak up, even though both Karin and Sakura gave him a weird look. 

“Naruto grew a bunch of extra arms,” he said. “Did you take any samples from those?”

As they spoke, Naruto was down to only one and a half extra arms. The half-arm was very annoying to pin down. 

“I mean, yeah…” Sakura said, waving at her collection of test tubes. Whatever else she was going to say was cut off by her randomly dropping the pipet she was holding. “Shit! My gel!”

Sakura ran over to the small tub of gently bubbling liquid, switching off the machine it was attached to and fretting as she squinted into it. 

“I thought you were doing a blot?” Sasuke asked. 

“The gel’s the first step,” Karin said, moving to the various tubes and slides Sakura had abandoned. “It separates proteins by size. IL-4 is pretty small so…” 

Karin deemed whatever Sakura was working on safe to leave alone, and went over to also squint into the small tub of gently bubbling liquid. 

“No, I think you’re good, I can see the bottom of the ladder,” Karin proclaimed.

Sasuke had… absolutely no idea what anyone was saying at this point. He went back to the pipette tips. It reminded him oddly of running a D-rank mission. Focus, do it right even if it’s boring, only half-listen to what nonsense your teammates were yelling about… 

Whatever the next step in the blot was, it involved waiting a few minutes for a machine to do something, and Karin and Sakura stood around it gossiping like two chunin killing time on front gate duty.

“...so I did like ninety heart transplant surgeries on rats, and only fourteen of them worked,” Karin said, sighing dramatically like this was the biggest pain in the world. 

Sakura had her hands hovering over her mouth, not touching her face due to the gloves, but definitely in the same genre of conversational cue as  _ I am covering my mouth so I don’t spit on you when I inevitably laugh at this.  _

“But it’s amazing you got the cells to make rat-sized hearts,” Sakura said, voice strained with repressed laughter. 

“Don’t flatter me,” Karin drawled. “You know how your heart decides chakra affinity?”

“Oh no,” Sakura squeaked. 

“Yeah, I made fourteen fucking  _ mokuton rats--” _

Sakura let out a peal of laughter loud enough that Kakashi looked over from where he and Orochimaru had spread out a bunch of sealing paper. 

“They all escaped, with their horrible tree powers,” Karin sighed. “Worst week of my life.”

If Sasuke remembered this particular week correctly, the rats were all found dead, pierced through by branches they couldn’t control. Karin was saved from revealing this bummer ending to her funny anecdote, because the machine beeped and Sakura opened a bag of… 

...evaporated milk… 

Sasuke stared suspiciously at the nail polish Karin had left behind. Science was  _ way _ weirder than he expected. 

“Hey, Sasuke-kun,” Karin suddenly called over to him. “If you’re done sorting the tips, go grab Suigetsu and have him show you how to use the autoclave.”

Sasuke thought that sounded like an important, science-y task, so he followed Karin’s directions to find Suigetsu. He was sitting in the kitchen, getting the coconut dessert that Sasuke had made the night before directly from the tupperware. 

“Oh wow, you really didn’t learn shit about lab work,” Suigetsu said when Sasuke gave him their new task. He slung an arm over Sasuke’s shoulders. “Come with me, friend, and I’ll show you the ways of lab grunt work…”

Apparently, they were just refilling the old tip boxes with new pipette tips, and then putting them in a special oven to sterilize them. Suigetsu referred to it as  _ the never-ending grind.  _

“Why did you throw all these away?” Suigetsu whined at Karin, pulling boxes out of the trash can. “Even if the tips are duds, the boxes are reusable, dumbass.”

“Because they pissed me off,” Karin snapped back. “Just like your stupid face pisses me off--”

“Karin,” Sakura called, “Are you done staining those slides?”

Karin sent Suigetsu one last, comically vicious glare, and then called back in her sweetest voice. “Coming, Sakura~!”

(“Yes,” Sasuke could hear Orochimaru tell Kakashi, “they’re always like that.”

“Ah,” Kakashi answered, “the springtime of youth…”

“...excuse me?”)

Refilling the tip boxes, one by one, from a bag of loose tips Suigetsu pulled from under one of the benches, was super annoying with one hand. Sasuke was sure it would be annoying with two hands, but it was especially annoying with one. 

“Yeah, well,” Suigetsu said, eyeing Sasuke’s face. Sasuke had not complained out loud, but Suigetsu knew him well enough to sense the irritation radiating off of him. “Imagine having to do this after you’ve been electrocuted so bad you can’t retain your physical form.”

Sasuke wrinkled his nose. He attempted to reign in his outward irritation. 

The autoclave took over an hour, so Sasuke recruited Suigetsu to help him with dinner prep. They used the last of the canned coconut milk on a curry, and Suigetsu braved opening a freezer to see if he could make a batch of ice for some dessert involving shaved ice.

The insides of the freezer… involved a lot of things that had melted, rotted, and then refrozen. 

“Welp,” Suigetsu said, letting it swing shut. “Nevermind. That’s gross as Karin’s flirting.” 

Sasuke had no idea how Karin and Suigetsu had managed to travel together without Sasuke preventing them from murdering each other. Juugo deserved some sort of award. 

Sasuke went back into the lab right on time to watch Karin open a tip box to present to Sakura with all the grandeur of a person opening a ring box to propose. 

“Eh?” Sakura said, blinking down at it. “You’re supposed to take tips in order, Karin, so you can…  _ oh! _ It’s cute!”

Sasuke stepped up to them, eyeing the tip box. Karin had removed enough tips so that the ones remaining were in the shape of a heart. That was… impressively unsubtle. 

Karin raised one eyebrow at Sakura. “Were you really going to lecture me on proper tip usage?”

Sakura’s cheeks went red. “Sh-shut up…” she mumbled. 

“Sasuke, my cute student who smells like curry,” Kakashi called, waving at him from across the lab. “Does your presence mean it’s dinner time?”

Orochimaru shot Sasuke an amused look as he led them all back to the kitchen, and he didn’t know what to do with it. Having his annoying teammates all hang out together was weird enough, but watching Kakashi and Orochimaru try to cooperate seemed like the kind of mindfuck one would experience in a particularly distressing genjutsu. 

He decided to try and ignore the problem by asking Karin, “What  _ is _ proper tip usage?”

Kakashi’s face lit up. “Ah, Sasuke-kun, what an impolite question for a lady--”

Sakura elbowed him in the ribs hard enough that Sasuke heard a definite crack. Karin gave Sakura’s elbow a small but very excited look before answering Sasuke. 

“Pipette tip boxes are the same standard dimensions as, like, tube racks and other pieces of lab equipment,” she said, with a casual wave. “You’re supposed to take them row by row, in order, so you can keep track of how many you’ve used. It’s super useful if you’re going to be pipetting into tens of things, where you might accidentally skip a tube or pipet twice into one.”

“That was much nicer than what you said to poor Hatori-kun,” Orochimaru mused. 

“Hatori had it coming,” Karin answered darkly. “He was going in a  _ spiral.” _

Suigetsu was already in the kitchen, having fetched Juugo from the clinic. He got up to help Sasuke move the food and a pile of plates to the table, in order to serve what was  _ the  _ weirdest dinner Sasuke had ever experienced. 

He’d had dinner with Orochimaru before, of course. He’d even had dinner with both Orochimaru  _ and _ Karin at once, a couple times. But those were all in private rooms with a selected few; Orochimaru would never deign to go into the Sound cafeterias.

He’d definitely never go into the  _ kitchen.  _

And Kakashi wouldn’t ever be passing him  _ napkins.  _

Sasuke decided that, since he was the prize pupil who’d accidentally brought Orochimaru here, and also probably the only one capable of completely controlling him in a fight, he’d take one for the team and sit next to Orochimaru.

For reasons Sasuke did not understand, Kakashi sat down across from them. 

“Maa, did you know, Sasuke-kun is quite the accomplished chef?” Kakashi asked. 

“I had no idea,” Orochimaru said, experimentally taking a bite of curry. “Sasuke-kun, this is delicious.”

It might have been the most impressed Orochimaru had ever looked with him. Sasuke didn’t know how to feel about that.

“Yes, when he was a genin, we always made him cook on field missions,” Kakashi said with a grave nod. This segued immediately into an embarrassing story about Sasuke trying and failing to remove the ink sac of a cuttlefish, which Orochimaru listened to with rapt attention. 

What the hell was happening? Sasuke looked around him for help. Next to him, Juugo was focusing too hard on what looked like notes about Naruto’s temple seal demon to be paying attention, and Suigetsu was all the way down at the other end of the table, looking openly disgusted with Karin and Sakura’s shenanigans. 

Now that her hands were free of contaminated gloves and washed, Karin was being incredibly hands-on with Sakura. 

She sat down closer to Sakura than necessary, so that there was no space whatsoever between their thighs. Currently, she was cooing something about Sakura’s chakra and brushing her fingers over Sakura’s byakugou seal. Sakura’s cheeks were pink, but Sasuke assumed she was fine with the touching-- he’d seen Sakura crack bones for less. 

The point was: Sakura and Karin were not going to help him. 

“How did you teach him Chidori?” Orochimaru asked Kakashi. “Because repurposing it into the Chidori Wave was a disaster. He kept shocking his feet--”

“How’s the research going?” Sasuke asked loudly, feeling just a little bit like he was losing his mind. 

This, at least, interrupted everyone’s conversations and got them to look at him. For some reason, it also made Sasuke’s cheeks hot. 

_ Sasuke didn’t blush.  _

“Kakashi-kun is surprisingly helpful,” Orochimaru said after a beat. 

“Oh shush, you flatterer,” Kakashi answered dryly. 

Kakashi only knew a grab-bag of seal work, but apparently the Fourth’s techniques had been influenced enough by Uzumaki Kushina’s own sealing prowess that Kakashi had some helpful insights into the temple seal. 

“Could you, um,” Karin started and then stuttered when everyone-- including Orochimaru-- turned to look at her at once. She banished her embarrassment as soon as it crossed her face, though, and said, “Could you explain it to me in more detail, back in the lab?”

Orochimaru smiled in a way that set alarm bells off in Sasuke’s head. “Why Karin, how rude of me. It completely slipped my mind that you’d have… connections… you might want to explore.”

Sasuke was  _ pretty  _ sure this was exactly how Orochimaru talked to people right before he split them open for a vivisection. 

“I’m interested too,” Sasuke said very quickly.

“...alright,” Orochimaru answered, with only the slightest bit of incredulity. Then he turned back to Karin and Sakura and said, “I’m interested to see what your biopsy found too.”

The conversation wandered after that, but while they were cleaning up, Karin stepped on Sasuke’s foot and whispered into his ear, “What are you doing, you dork?”

“I don’t want anyone left alone with him,” Sasuke murmured back.

Karin rolled her eyes. “I can take care of myself, you know.”

Then, she purposefully broke a plate and cut her palm on it. “Kyaa!” she screamed. “Sakura-chan, I’m hurt~!”

Sakura rushed over, her fingers already mint green with healing chakra. 

Sasuke was pretty sure Sakura would tell him to walk it off if he cut his hand like that. Sasuke didn’t even have a healing ability. 

Karin gave Sakura several very cutesy compliments about how nice her chakra was, and Suigetsu mimed vomiting into the sink until Juugo yanked him back by his ear. 

Sasuke sat through Orochiamru’s mini-fuinjutsu lesson with Karin. She took detailed notes and carefully copied the symbols Orochimaru wrote out on the chalkboard. She asked questions. Sasuke still had no idea what anything was, but he still felt like he was accomplishing something just by standing next to Karin and glaring. 

Without anything else to do, Sasuke also followed them over to the microscopes, where Sakura was sorting through biopsy slides. Orochimaru sat at one microscope, while Sakura passed slides to him and narrated what they were. 

“Do you want to see?” Karin asked Sasuke in a low voice, pointing at another microscope. 

“Yes,” Sasuke answered. 

Karin sat down first, turning on the microscope’s light and focusing it. She tapped a knob with one finger and told Sasuke it was the fine-focus, in case he needed to adjust it. 

He needed to adjust it a lot. Karin removed her glasses to use the microscope, and apparently her vision was  _ really _ bad. 

“Those are red blood cells,” Karin said of the random splash of small circles Sasuke was looking at. “Did you know Sakura can just, like, separate out cells by size right in the test tube with her  _ chakra--” _

“Karin,” Sasuke interrupted. 

“Right.” Karin cleared her throat. “Red blood cells. Notice they’re nucleated.”

“...okay,” Sasuke said. 

“Sorry,” Karin answered, sounding alarmingly like Sakura. “The darker dots are nuclei. Human red blood cells aren’t supposed to have them.”

Sasuke… knew what a nucleus was, and what red blood cells were, but he hadn’t known they didn’t have nuclei. Finally, he felt like he’d actually learned something, instead of just being confused. 

“So… that’s bad?” Sasuke asked. 

“It’s unclear,” Sakura interrupted him. “In normal adult blood, yes, it’d be a bad sign. But while physical transformation under the stress of intense chakra is a well-recorded phenomenon, the actual effects on health are not well-studied.”

Sakura  _ very _ casually set her hand on the back of Orochimaru’s chair and leaned on it. Orochimaru switched out a slide under the microscope and didn’t even twitch. 

“You did a bunch of studies on that, didn’t you, Sensei?” Karin asked. 

“Mm,” Orochimaru said, not looking up from the scope. Sasuke’s eyes were glued on Sakura’s hand on his chair. “It’s the primary principle behind the Cursed Seal.”

Sakura finally let go of his chair, but then  _ leaned over him _ like she didn’t have a fear in the world. 

“I thought that was just enzymatic activity?” Sakura asked. “I know chakra is involved, but it looked like it was only there to propagate the enzymes…”

Orochimaru leaned back in his chair, smiling up at Sakura. “Been studying Anko-chan, have you?” he asked, and Sakura finally took a step back from him. 

“I wouldn’t call it  _ studying _ her,” Sakura muttered. Her cheeks were pink again, but definitely not in a good way. 

“Nonsense,” Orochimaru answered, his smile still in place. “What is medical care if not an ongoing case study on an individual’s body? And I’m sure Anko’s case study is  _ fascinating.” _

Before Sasuke could figure how to make whatever horrible thing that was happening stop, Kakashi came up behind them and said in his best impression of Karin’s flirting: 

“You promised you’d spend all night with  _ me, _ Orochimaru-san.”

Orochimaru’s smile slipped ever so slightly.

Sasuke didn’t think he’d ever be thankful for his teacher being a gross weirdo, but he was fine with it if it made his  _ other _ teacher stop being a gross weirdo. 

“Of course,” Orochiamru finally said, his smile sliding right back into place. “How could I forget you, Kakashi-kun?”

He went to retreat to the mess of scrolls and ink he’d made with Kakashi, but not before turning back to Sakura and saying, “Anko’s seal was far from the final form. You should ask Karin-chan about Juugo’s case study.”

“...what?” Sakura asked when he was far enough away. “What was that?”

Karin sighed and then saddled up to Sakura, taking a hand in hers and rubbing little circles into the back of Sakura’s hand with her thumb.

“He’s just trying to get a rise out of you,” Karin said gently. “Seeing if you’ll dissect Juugo to save your friend.”

_ “What?” _ Sakura asked, dropping Karin’s hand. 

“She doesn’t mean it like that,” Sasuke cut in. “He just likes manipulation instead of giving straight answers. Karin can answer any questions about the Cursed Seal.”

“What does it have to do with Juugo?” Sakura asked, eyes wide.

This, at least, was a question Sasuke could answer on his own. Karin did most of the talking, but no one looked at Sasuke like he was a civilian child at a science fair when he put in his two cents. 

When they were done talking, Sakura still looked mildly dazed, and Karin suggested she go to bed. Sakura retreated out of the lab. 

"I guess my blot can block overnight," Sakura said as she drifted off. It was unclear to Sasuke if this was a coherent sentence or not.

“Are you kidding me,” Karin snarled when Sakura was gone. She pointed across the lab at Orochimaru, now showing Kakashi something from a box he’d taken out of a freezer. “Can’t he stay on task for more than a couple hours? He’s like a kid in a candy store...”

Sasuke thought this was an odd thing to say, given Karin had spent a lot of time that day being  _ highly _ distracted by Sakura.

“Sensei!” Karin yelled, stomping over to them. In a voice that was obviously pissed off but just sweet enough to still be considered polite, she asked, “Why are you showing off your DNA collection to the Hokage?”

“It’s my collection of Hokage DNA,” Orochimaru purred back. “I want him to make a donation to it.”

“But he won’t do it the  _ fun _ way,” Kakashi added. 

“Now, now,” Orochimaru answered, closing the box and putting it back in the freezer. “I told you-- I’d get too distracted to take a good sample if we did it  _ that _ way.”

“I don’t give DNA donations until the third date, anyway,” Kakashi said, and Sasuke literally saw black spots. 

_ What the FUCK was happening? _

He looked to Karin for help, but she looked like she was seriously considering what she was hearing, and she was interested in hearing more. 

“Sakura went to bed,” Sasuke said, and his own voice sounded far away in his own ears. “We should talk about watch shifts.”

“Such a  _ leader _ you’ve become, Sasuke-kun,” someone said, and Sasuke was unsure if it was Orochimaru or Kakashi, because he was having some sort of meltdown. 

Karin poked him in the side, and Sasuke managed to come back down to earth enough to get that he was being told to go grab Suigetsu and Juugo.

Yes. He could do that.  _ They _ wouldn’t betray him like this. 

The negotiations for watch shifts basically boiled down to Kakashi not wanting anyone but him and Sasuke to be on watch, because the Sound ninja might defer to weird orders from Orochimaru if left alone. Sasuke was sure he was worried about  _ Sasuke _ also doing something weird because of Orochimaru, but he also wanted to keep Sakura well-rested and ready for very intense emergency surgery if needed. 

Of course, what Kakashi  _ actually _ said was: “As your guests, it’s the least Sasuke and I can do to repay your hospitality.”

“That doesn’t make  _ any _ sense,” Suigetsu said. “Even if you let the medic sleep, there’s six of us. That’d make super easy shifts.”

“No, Kakashi-kun is right,” Orochimaru said blandly. “I’m going to bed, and I expect not to be bothered.”

He left. Karin raised her hand. 

“As assistant to the medic,” she said, “can I also skip watch duty?”

“Yes,” Kakashi answered immediately.

“We need two people per shift,” Juugo said. “One to watch Naruto, and one to watch the entrance.”

“Couldn’t you just reactivate the traps?” Kakashi asked. 

“If it were that easy, I’d’ve done it last night,” Sasuke said. Kakashi gave him a very condescending look. “Stop that. I know how  _ traps  _ work.”

Karin yawned loudly and said, “Yeah, he  _ actually _ knows about this one. If we wanted to reset the traps, we should have started hours ago.”

“Can’t Her Royal Bitchiness just do her sensing thing in her sleep?” Suigetsu asked. “That’s your  _ one _ redeeming quality, Karin.”

“At least I  _ have _ a redeeming quality,” Karin hissed back. 

The resulting argument was cut off by Orochimaru reappearing in the lab. 

“You gave Sakura-chan my bedroom,” he said to Sasuke, sounding perversely betrayed. “My things are in there.”

“You didn’t just kick her out?” Juugo asked, sounding more surprised than like it was a  _ suggestion.  _

“Tsunade trained her well,” Orochimaru said darkly. “I can’t remove her without her breaking the room. A typical Senju tactic.”

“We can always share--” Kakashi started. 

_ “Kakashi-sensei,” _ Sasuke interrupted, because he was not ready to listen to more of whatever was going on there. He was sure it was just Kakashi making his weird pervert jokes,  _ but what if it wasn’t? _ “We’re deciding watch shifts.”

“Whatever,” Karin said, reaching for the knocked over rack of lab coats no one had bothered to pick up. “If you woke her up anyway, then I’m going to go visit Sakura in one of these with nothing but my underwear on underneath and see what happens.”

“Ah, young love,” Orochimaru said as she flounced off. “I’m going to take Kabuto’s room. I don’t care who was using it. No one bother me.”

Kakashi eventually accepted that he and Sasuke could split Naruto Watch, while Juugo and Suigetsu split watch at the entrance. Karin  _ could _ probably watch the entrance in her sleep, but she usually had to do certain things to make sure she slept light enough to be aware enough to sense chakra, and she didn’t seem very interested in doing that tonight. 

Karin never came back from visiting Sakura. Sasuke didn’t know how he felt about that. 

Sasuke and Juugo got the first watches, and Suigetsu followed him to the clinic instead of going straight to bed. 

“You know,” Suigetsu said with a yawn, “this is the plot of  _ Icha Icha Violence.” _

“What is?” Sasuke asked. 

“You  _ know,” _ Suigetsu repeated, making a meaningless gesture with both hands. “The  _ thing _ with the girls.”

Sasuke grunted. 

“I mean, in the book, after they bang, like, three times,” Suigetsu continued, because Suigetsu never shut up, “the two kunoichi love interests decide to team up to kill the protagonist dude. You should be careful.”

“Sakura already tried to kill me,” Sasuke said, settling down in the rolling chair Juugo had been keeping vigil in. 

“Right, that’s why it’s  _ Karin’s _ turn,” Suigetsu said, “and she’s, like, way meaner. But I bet if you crawled in there with them, that pervert wouldn’t mind--”

Sasuke kicked him. 

**Notes for the Chapter:**

> I didn't _plan_ to make weird Kakashi-Orochimaru flirtations, but here we are. No one regrets this writing decision more than the writer. 
> 
> Some notes on the science: 
> 
> **Western blot:** A way to check to see if a protein of interest is present. It involves way too many fucking steps. I thought about doing a write up on what the steps are and where we see Sakura/Karin performing them (and what was done off-screen), but that seems like way too much work unless someone asks lmao. 
> 
> **Nail polish:** Sakura and Karin aren’t following any sort of real-life protocol for mounting and processing slides, but it is common to seal slides with nail polish. 
> 
> **Evaporated milk:** Also a normal ingredient for Western blots. 
> 
> **Proper tip usage:** You are supposed to go down the rows, but for some reason I always make diagonals unless I'm very consciously paying attention. I also used to be a big fan of making a diamond, or a spiral. I'm pretty sure what pattern you make with your tips is some sort of personality indicator. _Stay tuned for headcanons of pipette tip usage--_

**Author's Note:**

> If you're interested, [here's a bullet-point "fic" about how Karin became lab manager.](https://misfitmccoward.tumblr.com/post/638180058575536128/fic-ill-never-write-how-karin-came-to-be) Also I guess you can follow that to my tumblr if you want?


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